Switch assemblies have been developed which combine multiple switches in a single assembly. The multiple switches are operated using differing mechanical actuation. Such switch assemblies combine multiple switch functionality in an integrated device.
One particular use for switch assemblies is in a portable radiotelephone such as a cellular telephone. A radiotelephone commonly includes a menu system for controlling the functioning of the radiotelephone. For example, an electronic phone book of names and associated phone numbers is stored in memory. Contents of a portion of the memory, including several entries from the phone book, are displayed on a display. A controller responds to signals from a switch assembly or group of switches to control what data is displayed in the display from the memory. The controller thus allows a user to scroll through the phone book, select a name or number and initiate a call. The user manipulates the switches to navigate through the menu and phone book.
Different types of switches have been used for this purpose. In one application, three discrete switches with individual actuators are provided for menu control. This solution is inexpensive, because the switches can be purchased individually. However, this solution is physically large because the three switches are placed in series. In modern consumer electronics, the emphasis is on reducing the size of products. Large discrete switches are inconsistent with this trend. Also, the large size places the switches too far apart to be readily used by the fingers of one hand.
In another application, a rotary-click switch has been developed for menu control. A rotary thumbwheel may be turned to move in different directions, such as up and down, through a menu. The rotary element may be depressed or an associated switch may be depressed to perform the select function, such as selecting a menu item or initiating a call. This switch may be easily used by operating the thumbwheel with a thumb while holding the radiotelephone in one hand. This switch assembly has substantial disadvantages, however. For example, such switches are generally custom designed and built as combinations of rotary elements, one or more switches and potentiometers. Also, such switches tend to be large and expensive to use. Manufacturers always seek to reduce size, weight and manufacturing costs.
Accordingly, there is a need in the art for a switch assembly which is inexpensive to manufacture, is very small in size but which is comfortable and easy to use in conjunction with a portable radiotelephone.